Electrostatic Chuck and Method of Making Same

ABSTRACT

An electrostatic chuck includes a ceramic structural element, at least one electrode disposed on the ceramic structural element, and a surface dielectric layer disposed over the at least one electrode, the surface layer activated by a voltage in the electrode to form an electric charge to electrostatically clamp a substrate to the electrostatic chuck. The surface dielectric layer comprises: (i) an insulator layer of amorphous alumina, of a thickness of less than about 5 microns, disposed over the at least one electrode; and (ii) a stack of dielectric layers disposed over the insulator layer. The stack of dielectric layers includes: (a) at least one dielectric layer including aluminum oxynitride; and (b) at least one dielectric layer including at least one of silicon oxide and silicon oxynitride.

RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.61/937,135, filed on Feb. 7, 2014, the entire teachings of whichapplication are incorporated herein by reference.

BACKGROUND OF THE INVENTION

Electrostatic chucks (ESCs) are often utilized in the semiconductormanufacturing industry for clamping workpieces or substrates into afixed position on a support surface during plasma-based or vacuum-basedsemiconductor processes such as ion implantation, etching, chemicalvapor deposition (CVD), etc. Electrostatic clamping capabilities ofthese ESCs, as well as workpiece temperature control and hightemperature operation (i.e., operation in a range of between about 400°C. and about 750° C., such as at a temperature of about 500° C.), haveproven to be quite valuable in processing semiconductor substrates,workpieces or wafers, such as silicon wafers.

An electrostatic chuck generally includes an insulator body, such as aceramic (e.g., alumina, or the like) body, having an embedded electrodefor generating chucking force. The electrode is typically embedded byforming the ceramic body from two pieces, coating the electrode onto onepiece, and then bonding the two pieces together using an adhesive. Evenhigh temperature adhesives, however, typically fail at temperatureshigher than about 250° C.

Therefore, there is a need for an improved chuck design that reduces oreliminates the problems described above.

SUMMARY OF THE INVENTION

The invention generally is directed to an electrostatic chuck having adielectric layer deposited onto an insulator body.

In one version, an electrostatic chuck includes a ceramic structuralelement, at least one electrode disposed on the ceramic structuralelement, and a surface dielectric layer disposed over the at least oneelectrode, the surface dielectric layer activated by a voltage in theelectrode to form an electric charge to electrostatically clamp asubstrate to the electrostatic chuck. The surface dielectric layercomprises: (i) an insulator layer of amorphous alumina, of a thicknessof less than about 5 microns, disposed over the at least one electrode;and (ii) a stack of dielectric layers disposed over the insulator layer.The stack of dielectric layers includes: (a) at least one dielectriclayer including aluminum oxynitride; and (b) at least one dielectriclayer including at least one of silicon oxide and silicon oxynitride.

In some versions, the ceramic structural element can include alumina. Insome other versions, the ceramic structural element can include aluminumnitride. In yet other versions, the ceramic structural element caninclude silicon nitride. In certain versions, the electrode includes atleast one of: aluminum, titanium, molybdenum, silver, platinum, gold,nickel, tungsten, chromium, vanadium, ruthenium, iron, palladium, Kovar®(Kovar® is a registered U.S. Trademark of CRS Holdings, Inc., asubsidiary of Carpenter Technology Corporation of Wyomissing, Pa.,U.S.A.) or other nickel-cobalt ferrous alloy, manganese, and a nitride,such as titanium nitride. The at least one electrode can comprise athickness of less than about 0.5 microns, such as less than about 0.25microns. The electrostatic chuck can further comprise a heater. Theheater can include a resistive heater that is deposited and encapsulatedat a rear side of the ceramic structural element. The electrostaticchuck can further comprise at least one embedded temperature sensor.

The surface dielectric layer can have a thickness in a range of betweenabout 1 μm and about 250 μm. In some versions, the insulator layer ofamorphous alumina is deposited by atomic layer deposition over the atleast one electrode. The insulator layer can have a thickness in a rangeof between about 0.5 μm and about 2 such as about 1 μm. In certainversions, the stack of dielectric layers can include a first dielectriclayer deposited over the insulator layer, the first dielectric layerincluding silicon oxide, a second dielectric layer deposited over thefirst dielectric layer, the second dielectric layer including aluminumoxynitride, and a third dielectric layer deposited over the seconddielectric layer, the third dielectric layer including silicon oxide. Inthese specific versions, the thickness of the first dielectric layer canbe in a range of between about 10 μm and about 50 μm, such as about 20μm, the thickness of the second dielectric layer can be in a range ofbetween about 1 μm and about 20 μm, such as about 10 μm, and thethickness of the third dielectric layer can be in a range of betweenabout 10 μm and about 50 μm, such as about 20 μm. In some versions, thesurface dielectric layer can include at least one of yttria andzirconia. In some other versions, the surface dielectric layer caninclude silicon nitride.

In some versions, the stack of dielectric layers can include: a firstdielectric layer disposed over the insulator layer, the first dielectriclayer including aluminum oxynitride; and a second dielectric layerdisposed over the first dielectric layer, the second dielectric layerincluding at least one of silicon oxide and silicon oxynitride. In thesespecific versions, the thickness of the first dielectric layer can beabout 10 μm; and the second dielectric layer can have a thickness in arange of between about 40 μm and about 50 μm. A substrate contactingsurface of the electrostatic chuck can comprise a plurality ofprotrusions extending to a height above portions of the substratecontacting surface of the electrostatic chuck surrounding the pluralityof protrusions. The plurality of protrusions can comprise a height ofbetween about 3 microns and about 15 microns, such as a height ofbetween about 6 microns and about 8 microns. The plurality ofprotrusions can comprise at least one of etched protrusions anddeposited protrusions. At least one protrusion of the plurality ofprotrusions can comprise a substrate contacting surface coating, such asalumina deposited by atomic layer deposition, over an underlyingprotrusion.

In other versions, the electrostatic chuck can comprise a diffusionbarrier layer of amorphous alumina, deposited by atomic layerdeposition, disposed over the stack of dielectric layers. The diffusionbarrier layer can have a thickness in a range of between about 0.2 μmand about 1 μm. A plurality of protrusions, such as protrusionsincluding silicon oxide, can be deposited over the diffusion barrierlayer.

In some versions, the insulator layer of amorphous alumina can have aminimum dielectric strength of at least about 200 V per micron; such asbetween about 200 V per micron and about 400 V per micron; or of atleast about 500 V per micron; or of at least about 800 V per micron. Theat least one dielectric layer including aluminum oxynitride can comprisea minimum dielectric strength of at least about 50 V per micron. The atleast one dielectric layer including at least one of silicon oxide andsilicon oxynitride can comprise silicon oxide comprising a minimumdielectric strength of at least about 70 V per micron; and can comprisesilicon oxynitride comprising a minimum dielectric strength of at leastabout 70 V per micron.

In another version, the surface dielectric layer can be comprised of oneor more electrically insulating layers. At least one electricallyinsulating layer can be deposited with the thin film depositiontechnique of atomic layer deposition. In some versions, at least onelectrically insulating layer can be deposited with a thin filmdeposition technique such as chemical vapor deposition, plasma enhancedchemical vapor deposition, physical vapor deposition, electron beamdeposition, spray coating, atmospheric plasma deposition, high pressureplasma deposition, electrochemical deposition, sputter deposition, andany combination thereof. The surface dielectric layer can be comprisedof materials such as alumina, aluminum-oxy nitride, aluminum nitride,silicon oxide, silicon-oxy-nitride, silicon nitride, a transition metaloxide, a transition metal oxy-nitride, a rare earth oxide, a rare earthoxy-nitride, and any combination thereof. The surface dielectric layercan be comprised of one or more class of materials selected from thegroup consisting of a polycrystalline thin film, an amorphous thin film,and a quasi-crystalline thin film. The surface dielectric layer can beconformal. The surface dielectric layer can have a thickness between 1micron and 250 microns, such as between 10 microns and 70 microns, orbetween 25 microns and 50 microns. The surface dielectric layer can havethe ability to hold an electrical peak voltage of more than 500V, suchas more than 1000V, that is applied between the top and bottom of thesurface dielectric layer. The surface dielectric layer can be stable attemperatures between −150° C. and +750° C. The surface dielectric layercan fulfill the function of at least one of: (1) high strengthdielectric barrier, (2) dielectric layer with inherently low metalscontamination and low particle source, (3) a plasma etch resistantsurface, (4) an abrasion resistant surface.

In some versions, the electrostatic chuck can comprise a rounded edge onat least one of: a gas hole; a gas channel; a lift pin hole; and aground pin hole. A substrate contacting surface of the electrostaticchuck can comprise at least one of: alumina deposited by atomic layerdeposition, silicon oxide, silicon nitride, silicon oxynitride andsilicon-rich oxide. The insulator layer of amorphous alumina cancomprise a porosity of less than about 2 volume percent, such as lessthan about 1 volume percent, such as less than about 0.5 volume percent.The insulator layer of amorphous alumina can comprise alumina of formulaAl_(x)O_(y), where x is in the range of 1.8 to 2.2 and y is in the rangeof 2.6 to 3.4. The at least one dielectric layer including aluminumoxynitride can comprise aluminum oxynitride of formula AlO_(x)N_(y),where x is in the range of 1.4 to 1.8 and y is in the range of 0.2 to0.5. The at least one dielectric layer including at least one of siliconoxide and silicon oxynitride can comprise silicon oxide of formulaSiO_(x), where x is in the range of 1.8 to 2.4. The at least onedielectric layer including at least one of silicon oxide and siliconoxynitride can comprises silicon oxynitride of formula SiO_(x)N_(y)where x is in the range of 1.6 to 2.0 and y is in the range of 0.1 to0.5.

In yet another version, a method of making an electrostatic chuckincludes disposing at least one electrode onto a ceramic structuralelement, and depositing a surface dielectric layer over the at least oneelectrode, the surface dielectric layer activated by a voltage in theelectrode to form an electric charge to electrostatically clamp asubstrate to the electrostatic chuck. The electrode, ceramic structuralelement, and surface dielectric layer are as described above.

This invention has many advantages, such as enabling high temperatureprocessing of semiconductor substrates.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing will be apparent from the following more particulardescription of example embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingembodiments of the present invention.

FIG. 1A is a side view of an electrostatic chuck in accordance with oneversion of the invention.

FIG. 1B is a top view of an electrostatic chuck in accordance with oneversion of the invention.

FIG. 1C is a rear view of an electrostatic chuck in accordance with oneversion of the invention.

FIG. 2A is a schematic illustration of an electrostatic chuck having asurface dielectric layer in accordance with one version of theinvention.

FIG. 2B is a schematic illustration of an electrostatic chuck having asurface dielectric layer that includes an insulator layer over the atleast one electrode and a stack of three dielectric layers over theinsulator layer in accordance with one version of the invention.

FIG. 3 is a schematic illustration of an electrostatic chuck having asurface dielectric layer that includes an insulator layer over the atleast one electrode and a stack of two dielectric layers over theinsulator layer in accordance with one version of the invention.

DETAILED DESCRIPTION OF THE INVENTION

While this invention has been particularly shown and described withreferences to example embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the scope of the inventionencompassed by the appended claims.

While various compositions and methods are described, it is to beunderstood that this invention is not limited to the particularmolecules, compositions, designs, methodologies or protocols described,as these may vary. It is also to be understood that the terminology usedin the description is for the purpose of describing the particularversions or versions only, and is not intended to limit the scope of thepresent invention which will be limited only by the appended claims.

It must also be noted that as used herein and in the appended claims,the singular forms “a”, “an”, and “the” include plural reference unlessthe context clearly dictates otherwise. Thus, for example, reference toa “surface dielectric layer” is a reference to one or more surfacedielectric layers and equivalents thereof known to those skilled in theart, and so forth. Unless defined otherwise, all technical andscientific terms used herein have the same meanings as commonlyunderstood by one of ordinary skill in the art. Methods and materialssimilar or equivalent to those described herein can be used in thepractice or testing of versions of the present invention. Allpublications mentioned herein are incorporated by reference in theirentirety. Nothing herein is to be construed as an admission that theinvention is not entitled to antedate such disclosure by virtue of priorinvention. “Optional” or “optionally” means that the subsequentlydescribed event or circumstance may or may not occur, and that thedescription includes instances where the event occurs and instanceswhere it does not. All numeric values herein can be modified by the term“about,” whether or not explicitly indicated. The term “about” generallyrefers to a range of numbers that one of skill in the art would considerequivalent to the recited value (i.e., having the same function orresult). In some versions the term “about” refers to +10% of the statedvalue, in other versions the term “about” refers to ±2% of the statedvalue. While compositions and methods are described in terms of“comprising” various components or steps (interpreted as meaning“including, but not limited to”), the compositions and methods can also“consist essentially of” or “consist of” the various components andsteps, such terminology should be interpreted as defining essentiallyclosed-member groups.

In one version, shown in FIGS. 1A and 1B, an electrostatic chuck 100includes a ceramic structural element 1, at least one electrode 4 (shownin FIG. 1B as six electrodes 4) disposed on the ceramic structuralelement 1, and a surface dielectric layer 2, shown in FIG. 1A, depositedover the at least one electrode 4, the surface dielectric layer 2activated by a voltage in the electrode 4 to form an electric charge toelectrostatically clamp a substrate (not shown) to the electrostaticchuck 100. The electrostatic chuck 100 further includes a heater trace 3and a gas channel 5.

Turning to FIG. 1A, the ceramic structural element 1 can be made of avariety of ceramic materials, such as alumina (Al₂O₃), sapphire,aluminum nitride, silicon nitride, or the like. In one version, theceramic structural element is made of alumina (Al₂O₃), in a range ofbetween about 96% and about 99.8% pure alumina, such as greater than 97%alumina, or greater than 99.5% alumina, and annealed at temperaturesgreater than about 1000° C. to remove defects and stress points, andpolished at the front and rear sides. The ceramic structural element 1can be a disc, with a diameter of about 300 mm, and a thickness in arange of between about 2 mm and about 15 mm, such as a range of betweenabout 4 mm and about 12 mm, or a range of between about 6 mm and about10 mm, such as a thickness of about 10 mm. The side face of the ceramicstructural element 1 can be chamfered at an angle in a range of betweenabout 30 degrees and about 60 degrees, such as between about 40 degreesand about 50 degrees, or between about 43 degrees and about 47 degrees,such as at an angle of about 45 degrees, as shown in FIG. 1A.

Turning to FIG. 1B, the electrostatic chuck 100 further includes liftpin holes 6; ground pin holes 7; electrode pins 8; and gas holes 9. Theat least one electrode 4, can be a plurality of electrodes, such as 1electrode, 2 electrodes, 3 electrodes, 4 electrodes, 5 electrodes, 6electrodes (as shown in FIG. 1B), 7 electrodes, 8 electrodes, 9electrodes, or 10 electrodes. The electrodes 4 can be made of a varietyof metals, such as aluminum, titanium, molybdenum, silver, platinum,gold, nickel, tungsten, chromium, vanadium, ruthenium, iron, palladium,Kovar® or other nickel-cobalt ferrous alloy, or manganese; or a nitride,such as titanium nitride. In one version, the electrodes 4 are made ofnickel. The thickness of the electrodes 4 can be in a range of betweenabout 5 μm and about 10 nm, such as a range of between about 2 μm andabout 50 nm, or a range of between about 1 μm and about 200 nm. In oneversion, the thickness of the electrodes 4 is about 1 μm; in otherversions, the thickness of the electrodes 4 is less than about 0.5microns, or less than about 0.25 microns. The electrodes 4 can bedisposed on the insulator 1 by a variety of techniques, such as screenprinting, direct writing, plasma deposition followed by etch, plasmadeposition followed by mechanical patterning, electro-depositionfollowed by patterning, laser deposition, electroplating, and atomiclayer deposition followed by patterning.

Turning back to FIG. 1A, the surface dielectric layer 2 that isdeposited over the electrode 4 can be made of a variety of materials,and combinations of layers of materials. The choice of materials isdetermined by the following requirements for the material: 1) a highdielectric constant (i.e., a dielectric constant in a range of betweenabout 4 and about 50), 2) a thermal expansion coefficient suitable tomatch to the electrode 4 and the ceramic structural element 1, 3) lowparticle generation, 4) good electrical encapsulation of the electrode 4for a high voltage breakdown strength sufficient to hold off the appliedvoltage, 5) no metals contamination, such as contamination typicallyencountered in glass coatings (this requirement is particularlyimportant at high temperatures where elements in the coatings arerelatively mobile), 6) a surface dielectric layer 2 that is conformalover the electrodes 4, dense, and relatively free of pinholes or otherdefects (which may be achieved, for example, using ALD-depositedamorphous alumina), 7) a plasma etch resistant surface, and 8) anabrasion resistant surface. Within these requirements, the surfacedielectric layer 2 can be made of, for example, one or more of alumina,yttria, zirconia, aluminum oxynitride (AlON), aluminum nitride, siliconoxide, silicon oxynitride, silicon nitride, a transition metal oxide, atransition metal oxynitride, a rare earth oxide, or a rare earthoxynitride. The surface dielectric layer 2 can be a polycrystalline thinfilm, an amorphous thin film, or a quasi-crystalline thin film. Thesurface dielectric layer 2 can be a single layer, or a stack ofdielectric layers, such as a stack of 2 layers, 3 layers, 4 layers, 5layers, 6 layers, 7 layers, or 8 layers. The thickness of the surfacedielectric layer 2 can be in a range of between about 1 win and about250 μm, such as a thickness between about 10 μm and about 70 μm, or athickness between about 25 μm and about 50 μm. The thickness of thesurface dielectric layer 2 is determined in part by the effectivedielectric constant of the surface dielectric layer, such that a surfacedielectric layer with a lower dielectric constant will need to bethicker in order to provide sufficient dielectric breakdown strength,but the thermal expansion (in a temperature range of between, forexample, about −150° C. and about 750° C.) of a thicker surfacedielectric layer will be more challenging to match to the electrode 4and the ceramic structural element 1. To provide sufficient chuckingforce, the surface dielectric layer needs to hold an electrical peak DCpotential difference of more than about 500V, such as about 1000 V, thatis applied between the top and bottom of the surface dielectric layer 2.

The surface dielectric layer 2 can be deposited over the electrode 4 bya variety of thin film deposition techniques, such as atomic layerdeposition (ALD), chemical vapor deposition (CVD), plasma enhancedchemical vapor deposition, physical vapor deposition (PVD), electronbeam deposition, spray coating, atmospheric plasma deposition, highpressure plasma deposition, electrochemical deposition, and sputterdeposition. The specific thin film deposition technique can bedetermined by the choice of material, in that some thin film depositiontechniques are especially suitable for depositing certain materials,such as, for example, silicon oxide is typically deposited by CVD, AlONis typically deposited by PVD, alumina can be deposited by ALD, andyttria can be deposited by PVD.

The surface dielectric layer 2 can be a single electrically insulatinglayer deposited by any of the thin film deposition techniques discussedabove. In one version, the surface dielectric layer 2 is an insulatorlayer of alumina deposited by atomic layer deposition over theelectrodes 4. Atomic layer deposition of alumina, as described in moredetail below, typically involves heating the substrate to be coated to atemperature in a range of between about 200° C. and about 300° C. in aheated reactor, and alternately introducing first water (H₂O) and thentri-methyl aluminum (TMA) into the reactor, which react to produce asingle atomic layer of alumina (Al₂O₃). The cycle is repeated until thedesired thickness of the alumina layer is grown, which can be manythousands of cycles, such as, for example, 10,000 cycles to grow a layerof alumina of a thickness of about 1 (given that an atomic layer isapproximately 1 Angstrom thick). It takes many hours (e.g., about 33hours) to grow a 1 μm layer of alumina by ALD. As shown in FIG. 2A, itis possible to have a single layer of ALD grown alumina 210 form theentirety of the surface dielectric layer 2 over the electrode 4 andceramic structural element 1 of the electrostatic chuck 200, if thelayer of ALD grown alumina is sufficiently thick to withstand thepotential difference across the surface dielectric layer 2 duringoperation of the electrostatic chuck 200, but the required thicknessmight be on the order of several microns, which, under somemanufacturing circumstances, may not be readily practical given thelength of time required for ALD. For a thicker dielectric layer,therefore, it is generally desirable, as shown in FIG. 2B, to have thelayer of ALD grown alumina form an insulator layer 220 over theelectrode 4 and the ceramic structural element 1, and further include astack of dielectric layers deposited over the insulator layer 220. Amongother things, the stack of dielectric layers can be of a type that canbe formed to the desired thickness in a shorter length of time thanwould be an equivalent thickness consisting only of ALD grown alumina.As shown in FIG. 2B, the stack of dielectric layers can include a firstdielectric layer 230 deposited over the insulator layer 220, the firstdielectric layer 230 including silicon oxide (SiO_(x), x≈2), a seconddielectric layer 240 deposited over the first dielectric layer, thesecond dielectric layer 240 including aluminum oxynitride (AlON), and athird dielectric layer 250 deposited over the second dielectric layer,the third dielectric layer including silicon oxide (SiO_(x), x≈2). Inthese specific versions, the thickness of the first dielectric layer 230can be in a range of between about 10 pa and about 50 μm, such as about20 μm, the thickness of the second dielectric layer 240 can be in arange of between about 1 μm and about 20 μm, such as about 10 μm, andthe thickness of the third dielectric layer 250 can be in a range ofbetween about 10 μm and about 50 μm, such as about 20 μm. The thirddielectric layer can also include silicon nitride or aluminum oxide.Additionally, another layer of, for example, alumina can be depositedover the stack of dielectric layers, which may serve as a diffusionbarrier layer. Alternatively, the stack of dielectric layers can bedeposited over the electrode 4 without an insulator layer between theelectrode 4 and the stack of dielectric layers, optionally followed byanother layer of, for example, ALD grown alumina deposited over thestack of dielectric layers, which may serve as a diffusion barrierlayer.

FIG. 3 is a schematic illustration of an electrostatic chuck having asurface dielectric layer that includes an insulator layer over the atleast one electrode and a stack of two dielectric layers over theinsulator layer in accordance with one version of the invention. Theelectrostatic chuck includes a ceramic structural element 1, and one ormore outer heater traces 10 and inner heater traces 11. The heatertraces 10 and 11 can be screen-printed, and coated with an insulator,such as a thin-film glass coating. The electrodes 4 should be made of amaterial that has a low diffusivity through the dielectric at hightemperature. In particular, the electrodes 4 can be made of a variety ofmetals, such as aluminum, titanium, molybdenum, silver, platinum, gold,nickel, tungsten, chromium, vanadium, ruthenium, iron, palladium, Kovar®or other nickel-cobalt ferrous alloy, or manganese; or a nitride, suchas titanium nitride. The thickness of the electrodes 4 can be less thanabout 0.5 μm, such as less than about 0.25 μm. In one version,electrodes 4 can be formed, for example, of a conductor such as nickel,in a thickness of about 0.5 μm. The electrodes 4 are coated with anALD-deposited overlaying insulator layer 220 of amorphous alumina(Al₂O₃). The insulator layer 220 can be of a thickness up to about 5 μm,such as between about 0.5 μm and about 2 μm, such as about 1 μm. Abovethe insulator layer 220 is a stack of dielectric layers that includes afirst dielectric layer 260 and a second dielectric layer 270. In thisversion, the first dielectric layer 260 is formed of aluminum oxynitride(AlON), which can be of a thickness of, for example, about 10 μm; andthe second dielectric layer 270 is formed of silicon oxide or siliconoxynitride, which can be of a thickness of, for example, between about40 μm and about 50 μm. The first dielectric layer 260 can be formed byphysical vapor deposition (PVD) of aluminum oxynitride (AlON); and thesecond dielectric layer 270 can be formed by chemical vapor deposition(CVD) of silicon oxide or silicon oxynitride. In some versions, theinsulator layer 220 of amorphous alumina comprises alumina of formulaAl_(x)O_(y), where x is in the range of 1.8 to 2.2 and y is in the rangeof 2.6 to 3.4, which may be deposited by atomic layer deposition; thefirst dielectric layer 260 comprises aluminum oxynitride of formulaAlO_(x)N_(y), where x is in the range of 1.4 to 1.8 and y is in therange of 0.2 to 0.5, and may be deposited by physical vapor deposition;the second dielectric layer 270 comprises silicon oxide of formulaSiO_(x), where x is in the range of 1.8 to 2.4, which may be depositedby chemical vapor deposition; and/or the second dielectric layer 270comprises silicon oxynitride of formula SiO_(x)N_(y) where x is in therange of 1.6 to 2.0 and y is in the range of 0.1 to 0.5, which may bedeposited by chemical vapor deposition. Table 1 shows composition of theforegoing materials in an experimental electrostatic chuck in accordancewith a version of the invention, as measured by energy-dispersive X-rayspectroscopy (EDS) using 5 keV electron beam energy:

TABLE 1 Example of Composition of Layers of Electrostatic Chuck Atomic %N O Al Si ALD Al2O3 58 41 CVD SiOx 68.67 31.33 CVD SiOxNy 6.24 60.3833.38 PVD AlON 9.66 61.66 28.69 Al O N

In the version of FIG. 3, the first dielectric layer 260, formed ofaluminum oxynitride (AlON) can provide the advantage of functioning tomatch the coefficient of thermal expansion (CTE) from the amorphousalumina layer 220 to the oxide layer (second dielectric layer 270) aboveit. Further, the AlON of the first dielectric layer 260 can provide ahigh dielectric constant, which assists in providing greater clampforce. The second dielectric layer 270, which is formed of silicon oxideor silicon oxynitride, can provide the advantage of performing as a goodinsulator, with robust thermal properties, and of providing spacebetween the electrodes 4 and the clamped substrate. The seconddielectric layer 270 can include protrusions (or embossments) 18, whichextend to a height above surrounding areas of the second dielectriclayer 270, and which can be formed by etching of the second dielectriclayer 270. The height of the protrusions 18 can be in the range of fromabout 3 μm to about 15 μm, such as between about 6 μm and about 8 μm.Over the protrusions 18, the electrostatic chuck can include a diffusionbarrier layer 280, which can be formed of ALD-deposited amorphousalumina (Al₂O₃). In addition to serving as a diffusion barrier, layer280 can assist in providing a better high temperature contact for thesubstrate (as compared, for example, with oxide layer 270, which couldpotentially weld to the substrate at high temperatures). The diffusionbarrier layer 280 can have a thickness of between about 0.2 μm and about1 μm. Although various layers are described herein as being primarily aninsulator layer or a diffusion barrier layer, it should be understoodthat layers so identified may serve one or both functions of being aninsulator and a diffusion barrier. For example, insulator layer 220 canserve as both an insulator layer and a diffusion barrier. The purpose ofa diffusion barrier is, among other things, to prevent metalcontaminants from reaching a substrate, such as a semiconductor wafer,that is being clamped by the electrostatic chuck. In some cases,diffusion barrier layers may be as thin as, for example, about 0.2 μm orless, or less than about 10 nm thick.

Although the version of FIG. 3 shows the protrusions 18 as beingincluded in the second dielectric layer 270, there a variety ofdifferent possible arrangements for the protrusions 18. In accordancewith versions of the invention, a substrate contacting surface 19 of theelectrostatic chuck can include protrusions extending to a height aboveportions of the substrate contacting surface of the electrostatic chuckthat surround the protrusions. The protrusions can be formed by avariety of different possible methods, including etching and deposition.For example, protrusions 18 may be formed in an underlying layer, afterwhich a coating 280, such as a diffusion barrier of alumina deposited byatomic layer deposition, may be formed over the underlying protrusions18. In another example, protrusions can be formed by forming anunderlying planar layer, such as a planar layer of alumina deposited byatomic layer deposition, and then depositing protrusions on top of theplanar layer. For example, silicon oxide protrusions, of a height suchas 8 to 10 microns, can be deposited on top of a planar diffusionbarrier of alumina deposited by atomic layer deposition. The substratecontacting surface 19 of the electrostatic chuck can comprise a varietyof different possible materials, such as at least one of: aluminadeposited by atomic layer deposition, silicon oxide, silicon nitride,silicon oxynitride and silicon-rich oxide.

In accordance with versions of the invention, physical features on theceramic structural element 1 are treated to produce rounded edges, priorto applying the ALD-deposited amorphous alumina of insulator layer 220.This can include, for example, the gas holes, gas channels, lift pinholes and ground pin holes. Such features can be lapped to producerounded edges, prior to application of the ALD-deposited insulator layer220.

In accordance with versions of the invention, the layers ofALD-deposited amorphous alumina, such as insulator layer 220 anddiffusion barrier layer 280, can be low-defect or defect-free aluminalayers, with few or no pinhole defects, and have very high density. Theporosity of the ALD-deposited amorphous alumina layers can be low, suchas less than about 2 volume percent, less than about 1 volume percent,or less than about 0.5 volume percent, measured as the volume ofvoid-space as a percent of the total volume of alumina (including boththe void-space and the solid alumina). In addition, the ALD-depositedamorphous alumina of the insulator layer 220 can provide a highdielectric strength, such as a minimum dielectric strength of at leastabout 200 V per micron; for example between about 200 V per micron andabout 400 V per micron; or of at least about 500 V per micron; or of atleast about 800 V per micron. This dielectric strength means that theALD-deposited alumina is substantially pinhole defect-free, sincepinhole defects cause lower dielectric strength and result in arcing.The above dielectric strengths may be as measured using a larger testelectrode than a more typical test method, which uses a ball ofapproximately one quarter inch diameter as the test electrode on thesurface of the insulator layer 220, with the electrodes 4 beingconnected to ground. Instead, the dielectric strength may be measuredusing a larger test electrode, over an average area of the surface ofthe insulator layer 220, such as a full surface of the insulator layer220. Dielectric strengths given herein are measured at room temperature,although they may be approximately the same values at highertemperatures. Table 2 is a table of material properties of the layers220, 260 and 270 of the electrostatic chuck of FIG. 3, where “ALD Al₂O₃”corresponds to insulator layer 220, “PVD AlON” corresponds to firstdielectric layer 260, and “PECVD SiO_(x)” and “PECVD SiO_(x)N_(y)”correspond to possible choices for second dielectric layer 270:

TABLE 2 Example of Material Properties of Layers of Electrostatic ChuckDielectric Breakdown Elastic Modulus Hardness Strength (V/∃m) (GPa)(GPa) as-de- an- as-de- an- as-de- an- posited nealed posited nealedposited nealed ALD 563 289 225 265 10 11 Al2O3 PVD 67 59 200 145 9 7.5AlON PECVD 91 82 90 75 7 7 SiOx PECVD 104 79 95 85 6.5 6.5 SiOxNy

It can be seen in Table 1 that the dielectric breakdown strength ofinsulator 220 (“ALD Al₂O₃”), as annealed, is measure as 289 V permicron, and generally can be in the ranges given above; the dielectricbreakdown strength of first dielectric layer 260 (“PVD AlON”), asannealed, is measured as 59 V per micron, and generally can be at leastabout 50 V per micron; the dielectric breakdown strength of seconddielectric layer 270, for silicon oxide (“PECVD SiO_(x)”), as annealed,is measure as 82 V per micron, and generally can be greater than about70 V per micron; and the dielectric breakdown strength of seconddielectric layer 270, for silicon oxynitride (“PECVD SiO_(x)N_(y)”), asannealed is measured as 79 V per micron, and generally can be greaterthan about 70 V per micron.

Turning back to FIGS. 1A and 1B, the electrostatic chuck 100 can alsoinclude a system of gas channels 5 that are constructed at or near thefront side of the ceramic structural element 1 with one or more throughholes 9 to the backside to allow for gas (e.g., nitrogen, argon, orother gas) to be delivered to the gas channels 5 for providing thermalenergy exchange with the electrostatically clamped workpiece orsubstrate (not shown) by conduction and/or convection. The gas channels5 are arranged in a pattern that can be a radial pattern, as shown inFIG. 1B, or a star pattern, an axial pattern, a honeycomb pattern, aspiral pattern, or a straight line pattern. The cross section shape ofthe gas channels 5 can be one or more of a rectangular shape withrounded corners, a square shape, a half circular shape, an oval shape,and an elongated triangular shape. The cross section area of the gaschannels 5 can be between about 0.1 mm² and 5 mm². The surface of thechannels can be coated with an electrically insulating coating, or,alternatively, an electrically conducting coating. As shown in FIG. 1B,the gas channels 5 are provided with one or more gas feed holes 9 thatconnect to the backside of the ceramic structural element 1. The gasholes 9 are integrated into mounting posts 14 (see FIG. 1C) that can bebrazed or threaded into the ceramic structural element 1. The mountingposts 14 have the function to (1) secure the ceramic structural element1 to the base of the electrostatic chuck assembly, (2) minimize heatconduction between the ceramic structural element 1 and the base of theelectrostatic chuck assembly, and (3) allow for gas delivery from thebase of the electrostatic chuck assembly to the gas channels at thefront of the ceramic structural element.

Turning back to FIG. 1B, the ceramic structural element 1 also includesthrough holes 6 at various locations to allow for clearance of liftpins, and one or more embedded temperature sensors (not shown) mountedin holes provided from the rear side and reaching near the surface ofthe front side of the ceramic structural element, the temperaturesensors being held in place by one or more the following techniques:cementing, glass bonding, threaded securing, press fitting, brazing, andgluing. The embedded temperature sensors can be one or more of thefollowing: a resistance temperature detector (RTD), a thermocouple, athermistor, and a silicon band gap temperature sensor. The ceramicstructural element 1 can also include a gas seal ring (not shown),providing a continuous gas seal on the front side of the ceramicstructural element around the perimeter of the electrostatic chuck andaround the lift pin holes.

Turning to FIG. 1C, the electrostatic chuck 100 further includes aresistive heater comprised of outer heater zone 10 and inner heater zone11; an outer temperature sensor 12; an inner temperature sensor 13; amounting post 14; and a heater pin 15. The heater zones 10 and 11 aredeposited and encapsulated on the rear side of the ceramic structuralelement 1. The temperature of the outer and inner heater zones ismeasured by outer and inner embedded temperature sensors 12 and 13,respectively. The embedded temperature sensors 12 and 13 are mounted inholes provided from the rear side of the ceramic structural element 1and reaching near the surface of the front side of the ceramicstructural element 1, the embedded temperature sensors 12 and 13 beingheld in place by one or more of the following techniques: cementing,glass bonding, threaded securing, press fitting, brazing, and gluing.The temperature of the outer 10 and inner 11 heater zones can also bemonitored by measuring the temperature-dependent resistance of the outer10 and inner 11 heater traces, respectively.

Method of Manufacturing the Deposited Dielectric Electrostatic Chuck(DDESC)

The DDESC is constructed around a ceramic structural element which istypically an alumina disc, approximately 300 mm in diameter, about 10 mmthick with a chamfered side face, typically chamfered at around 45degrees. The alumina is typically made from 96% or 99.8% pure Al₂O₃material and has several features machined into it which will serve as(1) through holes for electrical contacts, (2) through holes to clearlift pins, blind holes for mounting electrical contact posts, throughholes to deliver gas from the backside to the front side, and a groovepattern at the front side that will serve as gas channels.

The ceramic structural element is cleaned and annealed in air toapproximately 900° C. for at least one hour, using a ramp rate of nomore than about 100° C./hr (for heating and cooling).

The heater is mounted to the rear side of the ceramic structuralelement. This is typically done by using a direct-writing method thatdeposits a conductive metallic heater trace, the metal being eithersilver or platinum, or the like. The heater trace is encapsulated with athin film glass coating to allow for (1) electrical shielding and (2)mechanical shielding. Alternatively, the heater can be encapsulatedlater with an insulator layer by means of a thin film depositiontechnique, such as ALD, PVD, or CVD. The heater is typically comprisedof two or more separate heater loops, also called heater zones, whichare powered independently.

The electrical connections are mounted onto the ceramic structuralelement. There are two connectors for each heater zone (typically two ormore heater zones), plus one connector for each electrode (typically sixelectrodes), plus one connector for each mounting post (typically sixmounting posts). The connections are typically all made of Kovar® pinsand all are brazed at the same time at around 900° C. in a controlledatmosphere. Other methods to secure the connections are possible, suchas cementing, using threaded connections, glass bonding, press-fitting,or diffusion bonding.

In addition to providing a strong mechanical connection, the mounting ofthe connections has the following requirements, in versions of theinvention: (1) The heater electrical connections need to have lowresistivity to the heater trace; (2) The mounting posts need to have aleak-tight, hermetic seal, as the mounting posts serve as the gas supplyfeed-through, in addition to providing the mechanical mount.

The front side of the ceramic structural element is lapped to provide asmooth and flat front side surface. At this stage, the front side showsonly the heads of six small Kovar® pins that are level with thesurrounding alumina structural element. Furthermore, the front sideshows three lift pin holes (through holes) and the grooves for the gaschannels. The top corners of the gas channels should be rounded toprovide the proper radius of the gas channel profile.

The rear side of the ceramic structural element has the encapsulatedheater, now electrically connected to the Kovar® connector that issticking out. In addition, there are six Kovar® pins sticking out forthe electrode connections and six Kovar® mounting posts. The rear sideof the ceramic structural element also has several open blind holes thatare utilized to mount embedded temperature sensors.

This ceramic assembly is cleaned in wet chemical baths and the frontside is coated with a metal film (typically nickel, platinum,nickel-chrome, molybdenum, or silver), approximately 1 micron inthickness, which is patterned into several equal-sized electrode shapes(typically six), by means of photo-masking and etching. The orientationand shape of the electrodes is such that each of the electrodes contactsone of the electrode connector pins, but each electrode is electricallyisolated from one another, thus providing six separate metal electrodesthat have electrical connections to the rear side of the ceramicstructural element.

This ceramic assembly is cleaned in wet chemical baths and annealed at atemperature of about 300° C. to anneal the metal and allow foroutgassing of any volatile compounds.

This ceramic assembly with rear side heater, electrical connectors andexposed metal electrodes at the front side receives a 1 micron aluminaatomic layer deposition (ALD) coating. The ALD deposition methodproduces a coating that is highly conformal, very dense and nearlypin-hole free and encapsulates the entire assembly (front side, rearside, holes, side faces, etc.). The ALD coating is typically performedat temperatures between 200° C. and 300° C. in a heated reactor (e.g.,having the reactor walls at a temperature of about 250° C. and theceramic assembly at a temperature of about 250° C.) and typicallyrequires about 10,000 gas deposition cycles alternating between pulsingwater (H₂O) for 0.015 seconds, waiting 5-10 seconds, and pulsing TMA(tri-methyl aluminum) for 0.015 seconds, waiting 5-10 seconds, andrepeating the cycle to produce a 1 micron thick film of alumina.

The ALD-coated assembly receives additional coatings of dielectricmaterial at the front side. This is to produce a dielectric barrier withgreater dielectric breakdown strength. The dielectric coating can becomprised of one or more layers, each layer carefully selected frommaterials with high dielectric strength and well matched thermalexpansion and interface adhesion coefficients. As an example, thedielectric coating stack can be comprised of 20 microns ofsilicon-oxide, 10 microns of aluminum oxy-nitride and 20 microns ofsilicon-oxide. Alternatively, the dielectric coating stack can becomprised of 10 microns of aluminum oxynitride (AlON), and 40 to 50microns of silicon oxide or silicon oxynitride. The coatings can beapplied by thin film deposition methods such as chemical vapordeposition (CVD), plasma enhanced chemical vapor deposition (PECVD),physical vapor deposition (PVD), electron beam deposition, spraycoatings, or atmospheric plasma deposition.

The embossment and gas seal ring structure is formed on top of thedielectric stack as described elsewhere. See PCT Application No.PCT/US2010/034667 published as WO 2010/132640 A2 on Nov. 18, 2010, PCTApplication No. PCTUS2011/037712 published as WO 2011/149918 A2 on Dec.1, 2011, and PCT Application No. PCT/US2011/050841 published as WO2012/033922 A2 on Mar. 15, 2012. The embossments can be made of avariety of materials, including materials such as silicon oxide(SiO_(x), x≈2), silicon nitride, or aluminum oxide; and can be etchedout of the material of the top layer of the dielectric stack, or made byother techniques discussed herein. A diffusion barrier layer ofALD-coated alumina of 1 micron thickness can be deposited over thedielectric coating stack.

Temperature sensors are cemented into the blind holes at the rear sideof the assembly. The temperature sensors can be, for example, resistancetemperature detectors (RTDs) or thermocouples (TCs).

The electrostatic chuck assembly is mounted on a base structure, whichholds heat shields, mounting provisions, electrical wiring and gassupply, thus completing the DDESC.

Although the invention has been shown and described with respect to oneor more implementations, equivalent alterations and modifications willoccur to others skilled in the art based upon a reading andunderstanding of this specification and the annexed drawings. Theinvention includes all such modifications and alterations and is limitedonly by the scope of the following claims. In addition, while aparticular feature or aspect of the invention may have been disclosedwith respect to only one of several implementations, such feature oraspect may be combined with one or more other features or aspects of theother implementations as may be desired and advantageous for any givenor particular application. Furthermore, to the extent that the terms“includes”, “having”, “has”, “with”, or variants thereof are used ineither the detailed description or the claims, such terms are intendedto be inclusive in a manner similar to the term “comprising.” Also, theterm “exemplary” is merely meant to mean an example, rather than thebest. It is also to be appreciated that features and/or elementsdepicted herein are illustrated with particular dimensions and/ororientations relative to one another for purposes of simplicity and easeof understanding, and that the actual dimensions and/or orientations maydiffer substantially from that illustrated herein.

Although the present invention has been described in considerable detailwith reference to certain versions thereof, other versions are possible.Therefore the spirit and scope of the appended claims should not belimited to the description and the versions contain within thisspecification.

The teachings of all patents, published applications and referencescited herein are incorporated by reference in their entirety.

What is claimed is:
 1. An electrostatic chuck comprising: a ceramic structural element; at least one electrode disposed on the ceramic structural element; and a surface dielectric layer disposed over the at least one electrode, the surface layer activated by a voltage in the electrode to form an electric charge to electrostatically clamp a substrate to the electrostatic chuck, the surface dielectric layer comprising: (i) an insulator layer of amorphous alumina, of a thickness of less than about 5 microns, disposed over the at least one electrode; and (ii) a stack of dielectric layers disposed over the insulator layer, the stack of dielectric layers including: (a) at least one dielectric layer including aluminum oxynitride; and (b) at least one dielectric layer including at least one of silicon oxide and silicon oxynitride.
 2. The electrostatic chuck of claim 1, wherein the surface dielectric layer has a thickness in a range of between about 1 μm and about 250 μm.
 3. The electrostatic chuck of claim 1, wherein the surface dielectric layer includes a silicon nitride layer.
 4. The electrostatic chuck of claim 1, wherein the surface dielectric layer includes a silicon oxynitride layer.
 5. The electrostatic chuck of claim 1, wherein the surface dielectric layer is comprised of one or more electrically insulating layers.
 6. The electrostatic chuck of claim 5, wherein at least one electrically insulating layer is deposited with the thin film deposition technique of atomic layer deposition.
 7. The electrostatic chuck of claim 5, wherein at least one electrically insulating layer is deposited with a thin film deposition technique selected from the group consisting of chemical vapor deposition, plasma enhanced chemical vapor deposition, physical vapor deposition, electron beam deposition, spray coating, atmospheric plasma deposition, high pressure plasma deposition, electrochemical deposition, and sputter deposition.
 8. The electrostatic chuck of claim 5, wherein the surface dielectric layer is comprised of materials selected from the group consisting of alumina, aluminum-oxy nitride, aluminum nitride, silicon oxide, silicon-oxy-nitride, silicon nitride, a transition metal oxide, a transition metal oxy-nitride, a rare earth oxide, and a rare earth oxy-nitride.
 9. The electrostatic chuck of claim 5, wherein the surface dielectric layer is comprised of one or more class of materials selected from the group consisting of a polycrystalline thin film, an amorphous thin film, and a quasi-crystalline thin film.
 10. The electrostatic chuck of claim 5, wherein the surface dielectric layer is conformal.
 11. The electrostatic chuck of claim 5, wherein the surface dielectric layer has a thickness between 1 micron and 250 microns.
 12. The electrostatic chuck of claim 11, wherein the surface dielectric layer has a thickness between 10 microns and 70 microns.
 13. The electrostatic chuck of claim 12, wherein the surface dielectric layer has a thickness between 25 microns and 50 microns.
 14. The electrostatic chuck of claim 1, wherein the surface dielectric layer has the ability to hold an electrical peak voltage of more than 500V that is applied between the top and bottom of the surface dielectric layer.
 15. The electrostatic chuck of claim 14, wherein the surface dielectric layer has the ability to hold an electrical peak voltage of more than 1000V that is applied between the top and bottom of the surface dielectric layer.
 16. The electrostatic chuck of claim 1, wherein the surface dielectric layer is stable at temperatures between −150° C. and +750° C.
 17. The electrostatic chuck of claim 1, wherein the surface dielectric layer fulfills the function of at least one of: (1) high strength dielectric barrier, (2) dielectric layer with inherently low metals contamination and low particle source, (3) a plasma etch resistant surface, (4) an abrasion resistant surface.
 18. The electrostatic chuck of claim 1, wherein the insulator layer of amorphous alumina is deposited by atomic layer deposition over the at least one electrode.
 19. The electrostatic chuck of claim 18, wherein the insulator layer has a thickness in a range of between about 0.5 μm and about 2 μm.
 20. The electrostatic chuck of claim 19, wherein the thickness of the insulator layer is about 1 μm.
 21. The electrostatic chuck of claim 1, wherein the stack of dielectric layers includes: i) a first dielectric layer deposited over the insulator layer, the first dielectric layer including silicon oxide; ii) the at least one dielectric layer including aluminum oxynitride, deposited as a second dielectric layer over the first dielectric layer; and iii) the at least one dielectric layer including at least one of silicon oxide and silicon oxynitride, deposited as a third dielectric layer over the second dielectric layer, the third dielectric layer including silicon oxide.
 22. The electrostatic chuck of claim 21, wherein the first dielectric layer has a thickness in a range of between about 10 μm and about 50 μm.
 23. The electrostatic chuck of claim 22, wherein the thickness of the first dielectric layer is about 20 μm.
 24. The electrostatic chuck of claim 21, wherein the second dielectric layer has a thickness in a range of between about 1 μm and about 20 μm.
 25. The electrostatic chuck of claim 24, wherein the thickness of the second dielectric layer is about 10 μm.
 26. The electrostatic chuck of claim 21, wherein the third dielectric layer has a thickness in a range of between about 10 μm and about 50 μm.
 27. The electrostatic chuck of claim 26, wherein the thickness of the third dielectric layer is about 20 μm.
 28. The electrostatic chuck of claim 1, wherein the ceramic structural element includes alumina.
 29. The electrostatic chuck of claim 1, wherein the ceramic structural element includes aluminum nitride.
 30. The electrostatic chuck of claim 1, wherein the ceramic structural element includes silicon nitride.
 31. The electrostatic chuck of claim 1, wherein the at least one electrode includes at least one of: aluminum, titanium, molybdenum, silver, platinum, gold, nickel, tungsten, chromium, vanadium, ruthenium, iron, palladium, nickel-cobalt ferrous alloy, manganese, and a nitride.
 32. The electrostatic chuck of claim 31, wherein the at least one electrode includes titanium nitride.
 33. The electrostatic chuck of claim 1, wherein the at least one electrode comprises a thickness of less than about 0.5 microns.
 34. The electrostatic chuck of claim 1, wherein the at least one electrode comprises a thickness of less than about 0.25 microns.
 35. The electrostatic chuck of claim 1, wherein the surface dielectric layer includes at least one of yttria and zirconia.
 36. The electrostatic chuck of claim 1, wherein the surface dielectric layer includes silicon nitride.
 37. The electrostatic chuck of claim 1, wherein the stack of dielectric layers includes: i) the at least one dielectric layer including aluminum oxynitride, being a first dielectric layer disposed over the insulator layer; and ii) the at least one dielectric layer including at least one of silicon oxide and silicon oxynitride, being a second dielectric layer disposed over the first dielectric layer.
 38. The electrostatic chuck of claim 37, wherein the thickness of the first dielectric layer is about 10 μm.
 39. The electrostatic chuck of claim 37, wherein the second dielectric layer has a thickness in a range of between about 40 μm and about 50 μm.
 40. The electrostatic chuck of claim 1, wherein a substrate contacting surface of the electrostatic chuck comprises a plurality of protrusions extending to a height above portions of the substrate contacting surface of the electrostatic chuck surrounding the plurality of protrusions.
 41. The electrostatic chuck of claim 40, wherein the plurality of protrusions comprise a height of between about 3 microns and about 15 microns.
 42. The electrostatic chuck of claim 41, wherein the plurality of protrusions comprise a height of between about 6 microns and about 8 microns.
 43. The electrostatic chuck of claim 40, wherein the plurality of protrusions comprise at least one of etched protrusions and deposited protrusions.
 44. The electrostatic chuck of claim 40, wherein at least one protrusion of the plurality of protrusions comprises a substrate contacting surface coating over an underlying protrusion.
 45. The electrostatic chuck of claim 44, wherein the substrate contacting surface coating comprises alumina deposited by atomic layer deposition.
 46. The electrostatic chuck of claim 1, further comprising a diffusion barrier layer of amorphous alumina deposited by atomic layer deposition, disposed over the stack of dielectric layers.
 47. The electrostatic chuck of claim 46, wherein the diffusion barrier layer has a thickness in a range of between about 0.2 μm and about 1 μm.
 48. The electrostatic chuck of claim 46, further comprising a plurality of protrusions deposited over the diffusion barrier layer.
 49. The electrostatic chuck of claim 48, wherein the plurality of protrusions deposited over the diffusion barrier layer comprise silicon oxide.
 50. The electrostatic chuck of claim 1, wherein the insulator layer of amorphous alumina has a minimum dielectric strength of at least about 200 V per micron.
 51. The electrostatic chuck of claim 50, wherein the insulator layer of amorphous alumina has a minimum dielectric strength of between about 200 V per micron and about 400 V per micron.
 52. The electrostatic chuck of claim 50, wherein the insulator layer of amorphous alumina has a minimum dielectric strength of at least about 500 V per micron.
 53. The electrostatic chuck of claim 50, wherein the insulator layer of amorphous alumina has a minimum dielectric strength of at least about 800 V per micron.
 54. The electrostatic chuck of claim 1, wherein the at least one dielectric layer including aluminum oxynitride comprises a minimum dielectric strength of at least about 50 V per micron.
 55. The electrostatic chuck of claim 1, wherein the at least one dielectric layer including at least one of silicon oxide and silicon oxynitride comprises silicon oxide comprising a minimum dielectric strength of at least about 70 V per micron.
 56. The electrostatic chuck of claim 1, wherein the at least one dielectric layer including at least one of silicon oxide and silicon oxynitride comprises silicon oxynitride comprising a minimum dielectric strength of at least about 70 V per micron.
 57. The electrostatic chuck of claim 1, further comprising a heater.
 58. The electrostatic chuck of claim 57, wherein the heater comprises a resistive heater that is deposited and encapsulated at a rear side of the ceramic structural element.
 59. The electrostatic chuck of claim 57, further comprising at least one embedded temperature sensor.
 60. The electrostatic chuck of claim 1, comprising a rounded edge on at least one of: a gas hole; a gas channel; a lift pin hole; and a ground pin hole.
 61. The electrostatic chuck of claim 1, wherein a substrate contacting surface of the electrostatic chuck comprises at least one of: alumina deposited by atomic layer deposition, silicon oxide, silicon nitride, silicon oxynitride and silicon-rich oxide.
 62. The electrostatic chuck of claim 1, wherein the insulator layer of amorphous alumina comprises a porosity of less than about 2 volume percent.
 63. The electrostatic chuck of claim 1, wherein the insulator layer of amorphous alumina comprises a porosity of less than about 1 volume percent.
 64. The electrostatic chuck of claim 1, wherein the insulator layer of amorphous alumina comprises a porosity of less than about 0.5 volume percent.
 65. The electrostatic chuck of claim 1, wherein the insulator layer of amorphous alumina comprises alumina of formula Al_(x)O_(y), where x is in the range of 1.8 to 2.2 and y is in the range of 2.6 to 3.4.
 66. The electrostatic chuck of claim 1, wherein the at least one dielectric layer including aluminum oxynitride comprises aluminum oxynitride of formula AlO_(x)N_(y), where x is in the range of 1.4 to 1.8 and y is in the range of 0.2 to 0.5.
 67. The electrostatic chuck of claim 1, wherein the at least one dielectric layer including at least one of silicon oxide and silicon oxynitride comprises silicon oxide of formula SiO_(x), where x is in the range of 1.8 to 2.4.
 68. The electrostatic chuck of claim 1, wherein the at least one dielectric layer including at least one of silicon oxide and silicon oxynitride comprises silicon oxynitride of formula SiO_(x)N_(y) where x is in the range of 1.6 to 2.0 and y is in the range of 0.1 to 0.5. 